Different Anatomical Subsites of Colon Cancer and Mortality: A Population-Based Study

The Role of Tumor Location on Endoscopic and Surgical Management of Malignant Colon Polyps

BACKGROUND

Endoscopic polypectomy could be an appropriate, definitive treatment for pathologic T1 (pT1) colon polyps without high-risk features. Prior studies suggested worse prognosis for proximal versus distal advanced-stage colon cancers following curative treatment. However, there is limited evidence on the prognostic impact of tumor location for pT1s.

PATIENTS AND METHODS

This was a retrospective cohort study using the Surveillance, Epidemiology, and End Results database to identify adults with T1NxMx or T1N0-3M0/x colon adenocarcinoma from 2000 to 2019.

RESULTS

A total of 3398 patients underwent endoscopic polypectomy (17% proximal) and 28,334 had a partial colectomy (49% proximal) for pT1 adenocarcinoma. Following endoscopic polypectomy, 5-year overall and cancer-specific survival rates were 64% and 91% for proximal versus 83% and 96% for distal polyps, compared with 82% and 95% for proximal versus 88% and 97% for distal tumors after colectomy. In multivariable models, there was a greater difference in overall survival between proximal and distal polyps for those who underwent endoscopic versus surgical resection [hazard ratio (HR) 1.73, 95% confidence interval (CI) 1.49-2.02 vs. HR 1.13, 95% CI 1.08-1.18]. Patients with proximal versus distal polyps who underwent polypectomy also exhibited increased cancer-specific mortality (HR 1.94, 95% CI 1.37-2.75). However, cancer-specific survival variations based on tumor location were no longer observed in patients undergoing partial colectomy (HR 1.09, 95% CI 0.98-1.21).

CONCLUSIONS

Proximal tumor location was independently associated with worse overall and cancer-specific survival following endoscopic polypectomy. However, after colectomy, the cancer-specific disparity based on tumor laterality was mitigated. These findings suggest that proximal location may be considered a high-risk feature in endoscopic polypectomy.

Risk of colon cancer-related death in people who had cancer in the past

BACKGROUND

The rate of second primary malignancies (SPM) is gradually increasing. Yet, the risk of death from primary cancer vs. SPM is still not well understood. In this study, we investigated the survival of patients with colorectal cancer (as SPM) who had cancer in the past (prior cancer) and the risk factors of SPM death in this population.

MATERIALS AND METHODS

Based on the Surveillance, Epidemiology, and End Results (SEER) database, we identified 1866 colon cancer patients with prior cancer in our main cohort and 43,959 colon cancer patients, including 37,440 patients with colon cancer as only malignancy and 6519 patients with colon cancer as subsequent colon cancer (SCC), in a second cohort and 3429 colon cancer patients, including 2371 patients with prior colon cancer (PCC) and 1058 patients with colon cancer as SPM, in a third cohort. After propensity score matching, 6519 pairs of subjects were identified in second cohort.

RESULTS

Patients with prior prostate and breast cancer had a higher risk of developing colon cancer compared to those with gastrointestinal cancer. Also, colon cancer patients with different prior cancer had different survival rates. Furthermore, except for prior lung cancer (52.78 vs. 25.93%), most subjects died due to colon cancer complications. The ratio of colon cancer deaths to prior cancer deaths in patients with a low stage and high stage was 1.51 and 6.64, respectively. In addition, colon cancer-specific survival (CSS) and OS rates were significantly lower in subjects with colon cancer as the SPM than in those with PCC. Also, compared with PCC, SPM was associated with OS and CSS with HR 1.59 (95 CI 1.43-1.78) and HR 2.00 (95% CI 1.70-2.36). Furthermore, compared with only colon cancer, SCC was associated with OS and CSS with HR 1.23 (95 CI 1.17-1.29) and HR 1.13 (95% CI 1.06-1.21).

CONCLUSIONS

Prior cancer was found to have an adverse impact on OS in patients with colon cancer (secondary cancer), most of whom died due to colon cancer as secondary cancer itself rather than prior cancer. Early detection and treatment strategies should be investigated in this population.

The Bioinformatics-Based Analysis Identifies 7 Immune-Related Genes as Prognostic Biomarkers for Colon Cancer

Colon cancer poses a great threat to human health. Currently, there is no effective treatment for colon cancer due to its complex causative factors. Immunotherapy has now become a new method for tumor treatment. In this study, 487 DEGs were screened from The Cancer Genome Atlas (TCGA) database and ImmPort database, and GeneOntology (GO) functional enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis was performed. Hierarchical clustering of all samples revealed a significant correlation between colon cancer and immunity. The weighted gene co-expression network analysis (WGCNA) algorithm was used to identify key gene modules associated with immunity in colon cancer, here, module grey60 showed the highest correlation. A protein-protein interaction (PPI) network was constructed using the STRING database to screen hub genes, and subsequently, 7 immune-related genes the most closely associated with colon cancer were identified by differential expression in cancer and paracancer. Finally, a risk prediction model was developed using least absolute shrinkage and selection operator (LASSO) COX analysis, and the accuracy of the model was validated by GSE14333. This study determined that IRF4 and TNFRSF17 were immune-related genes in colon cancer, providing immune-related prognostic biomarkers for colon cancer.

The rise of proximal colorectal cancer: a trend analysis of subsite specific primary colorectal cancer in the SEER database

Background

Colorectal cancer (CRC) is the third most common cancer worldwide and the second leading cause of cancer-related deaths. Given the significant prevalence of CRC, regular preventative screening is required. CRCs in different locations of the colon have variable molecular pathogenesis, gross appearance, and general disease outcomes. While the overall incidence of CRC has been decreasing, the decrease in proximally located CRC significantly lags behind the other forms of CRC. The objective of this study was to establish independent risk factors for proximal CRC for better identification of populations at risk for closer CRC monitoring and observation.

Methods

A time-trend analysis was conducted using data from the National Cancer Institute’s Surveillance, Epidemiology, and End Results (SEER) database from 1973-2007, comparing patient characteristics (age, sex, race/ethnicity, year of diagnosis, age of diagnosis, tumor grade, tumor stage, and urban-rural setting) between CRCs originating in different locations.

Results

Analysis demonstrated that black race, female sex, age over 60, and being diagnosed in the 21st century (rather than 20th) were associated with an increased risk of proximal CRC compared to CRCs originating in other locations.

Conclusions

Our study showed that black race, female sex, and age over 60 independently increased the likelihood of proximal CRC diagnosis. Furthermore, CRC trends identify an increasing proportion of all CRCs being of proximal origin. It is imperative that patients undergo regularly scheduled complete colonoscopies by trained endoscopists, especially if they belong to the high-risk groups previously identified.

Telomere maintenance in interplay with DNA repair in pathogenesis and treatment of colorectal cancer

Colorectal cancer (CRC) continues to be one of the leading malignancies and causes of tumour-related deaths worldwide. Both impaired DNA repair mechanisms and disrupted telomere length homeostasis represent key culprits in CRC initiation, progression and prognosis. Mechanistically, altered DNA repair results in the accumulation of mutations in the genome and, ultimately, in genomic instability. DNA repair also determines the response to chemotherapeutics in CRC treatment, suggesting its utilisation in the prediction of therapy response and individual approach to patients. Telomere attrition resulting in replicative senescence, simultaneously by-passing cell cycle checkpoints, is a hallmark of malignant transformation of the cell. Telomerase is almost ubiquitous in advanced solid cancers, including CRC, and its expression is fundamental to cell immortalisation. Therefore, there is a persistent effort to develop therapeutics, which are telomerase-specific and gentle to non-malignant tissues. However, in practice, we are still at the level of clinical trials. The current state of knowledge and the route, which the research takes, gives us a positive perspective that the problem of molecular models of telomerase activation and telomere length stabilisation will finally be solved. We summarise the current literature herein, by pointing out the crosstalk between proteins involved in DNA repair and telomere length homeostasis in relation to CRC.

Better survival of right-sided than left-sided stage II colon cancer: a propensity scores matching analysis based on SEER database

BACKGROUND/AIMS

Most studies have found that right-sided colon cancer (RCC) has worse prognosis than left-sided colon cancer (LCC), especially in stage III, but the reported prognosis of stage II colon cancer is variable. This study aimed to evaluate the impact of tumor location on survival outcomes in stage II colon cancer.

MATERIALS AND METHODS

Patients with stage II colon cancer were identified in the Surveillance, Epidemiology, and End Results database from 2004 to 2009. The effect of tumor location on overall survival and cancer-specific survival was analyzed using Cox proportional hazards regression models and propensity score matching.

RESULTS

Of 16,519 patients, 69.6% had RCC and30.4% had LCC. In unadjusted analyses, RCC had a 13% increased overall mortality risk (hazards ratio [HR], 1.13; 95% confidence interval [CI], 1.07-1.19; p<0.001) but an18% reduction in cancer-specific mortality risk compared with LCC (HR, 0.82; 95% CI, 0.76-0.89; p<0.001). After propensity scores matching analyses, RCC had a 21% reduced overall mortality risk (HR, 0.79; 95% CI, 0.72-0.87; p<0.001) and a 49% reduction in cancer-specific mortality risk compared with LCC (HR, 0.51; 95% CI, 0.44-0.60; p<0.001).

CONCLUSION

When adjusted for multiple clinicopathological features, stage II RCC showed better prognosis than stage II LCC.

Predictive Risk Factors and Online Nomograms for Synchronous Colon Cancer With Liver Metastasis

Objectives

To develop and validate predictive nomograms of cancer specific survival (CSS) and overall survival (OS) for synchronous colon cancer with liver metastasis (SCLM) patients.

Methods

Patients with pathologically diagnosed colon cancer with liver metastasis were retrieved from the SEER database between 2010 and 2015. Only SCLM patients were included. Univariate and multivariate cox regression analyses were conducted to identify the potential predictors of patients’ survival outcomes. The selected variables were integrated to create predictive nomograms via R tools. Furthermore, the concordance index Harrell’s C statistic (C-index) was calculated to describe the discrimination of nomograms. Calibration (1000 bootstrap resamples) curves were plotted to compare the predictions of nomograms with the observed outcomes. Decision curve analysis (DCA) and clinical impact curves were performed to evaluate the clinical effects of nomograms.

Results

A total of 22,378 SCLM patients were included. The median time of OS and CSS was 13 and 17 months, respectively. The 1-, 2-, and 3-year rate of OS was 50.6, 28.1, and 14.8%, respectively. While the 1-, 2-, and 3-year rate of CSS was 58.7, 36.8, and 22.5%, respectively. SCLM patients with increased age, left primary tumor location, AJCC IVb stage, and no chemotherapy were associated with an obviously reduced OS and CSS. Variables including age, histological grade, T/N/M stage, tumor size, bone/lung metastasis, CEA, surgery of primary site, and chemotherapy were closely related to the prognoses of SCLM patients. Nomograms of OS and CSS were built and displayed online for convenient utilization. The C-index of OS and CSS monograms were 0.74 and 0.73, respectively, indicating relatively good discrimination of the nomograms. The calibration curves suggested a good agreement between the actual observation and the nomogram prediction. DCAs and clinical impact curves reflected favorable potential clinical effects of predictive nomograms.

Conclusion

Chemotherapy, surgery of primary site, and age were important independent risk factors for the CSS and OS of SCLM patients. We built and validated two reliable nomograms of OS and CSS to predict the prognoses of SCLM patients, which can be accessed online at (https://predictive-tool.shinyapps.io/CSS-DynNomapp/; https://predictive-tool.shinyapps.io/OS-DynNomapp/).

Effect of KRAS and NRAS mutations on the prognosis of patients with synchronous metastatic colorectal cancer presenting with liver-only and lung-only metastases

It has been reported that 20–25% of patients with colorectal cancer (CRC) have metastases at the time of diagnosis. Liver and lung are the most common metastatic sites. The aim of the present study was to investigate the association of KRAS and NRAS mutations with clinicopathological features and prognosis of patients with initial liver-metastasis only (LiM-only) or lung-metastasis only (LuM-only) metastatic CRC (mCRC). Overall, 166 patients with CRC with initial LiM-only (n=124) and LuM-only (n=42) were retrospectively analyzed from January 2014 to December 2017. The median follow-up time was 19.2 months (1.0–57.1 months). Patient characteristics at diagnosis were collected. Genomic DNA was isolated from frozen primary CRC tissues for targeting KRAS and NRAS. Patients with LuM-only were significantly older compared with those with LiM-only (65.5 vs. 61.5 years; P=0.05). There was no significant differences between the LiM-only and LuM-only groups in terms of sex, location of the primary tumor, serum carcinoembryonic antigen level, histological grade and RAS mutation status. KRAS mutations were detected in 43 (41.0%) patients with LiM-only and 13 (35.1%) patients with LuM-only. The overall survival time (OS) of LuM-only was more favorable compared with that of patients with LiM-only (44.5 vs. 24.7 months); however, there was no significant difference (P=0.095). The progression-free survival (PFS) and OS in the RAS wild-type group were significantly improved compared with the RAS mutant cohorts (P=0.004 and P=0.031, respectively) in the LiM-only group. In patients with stage IV CRC, those with synchronous LiM-only mCRC had a higher incidence of metastasis but a less favorable PFS and OS compared with patients with LuM-only. RAS mutation status exhibited a significant association with the survival outcome in patients with LiM-only mCRC.

Tumor sidedness influences prognostic impact of lymph node metastasis in colon cancer patients undergoing curative surgery

This study aimed to evaluate prognostic impacts of the number of lymph nodes (LNs) examined and LN ratio on cancer-specific mortality after surgery in patients with right-sided colon cancer (RCC) or left-sided colon cancer (LCC) using the Surveillance, Epidemiology, and End Results database. Number of LNs examined and LN ratio were treated as categorical and/or continuous. Competing risks proportional hazards regressions adjusted by propensity score were performed. All included patients had stage I, II, or III disease, and 45.1% of them had RCC. RCC and LCC patients with high level of LNs examined had better prognosis after segmental resection or hemicolectomy. RCC and LCC patients with higher LN ratio had worse prognosis regardless of surgery. Survival benefit of having high level of LNs examined was observed in RCC patients with stage I, II, or III disease, but only in LCC patients with stage II disease. Both higher LN ratio and high level of LN were negative prognostic factors for cancer-specific mortality in stage III patients regardless of tumor sidedness. In conclusion, RCC patients in various conditions had worse or comparable prognosis compared to their LCC counterparts, which reflected the severity of LN metastasis.

The Impact of Primary Tumor Location in Synchronous Metastatic Colorectal Cancer: Differences in Metastatic Sites and Survival

Purpose

We explored differences in survival between primary tumor locations, hereby focusing on the role of metastatic sites in synchronous metastatic colorectal cancer (mCRC).

Methods

Data for patients diagnosed with synchronous mCRC between 1989 and 2014 were retrieved from the Netherlands Cancer registry. Relative survival and relative excess risks (RER) were analyzed by primary tumor location (right colon (RCC), left colon (LCC), and rectum). Metastatic sites were reported per primary tumor location. Survival was analyzed for metastatic sites combined and for single metastatic sites.

Results

In total, 36,297 patients were included in this study. Metastatic sites differed significantly between primary tumor locations, with liver-only metastases in 43%, 54%, and 52% of RCC, LCC, and rectal cancer patients respectively (p < 0.001). Peritoneal metastases were most prevalent in RCC patients (33%), and lung metastases were most prevalent in rectal cancer patients (28%). Regardless of the location of metastases, patients with RCC had a worse survival compared with LCC (RER 0.81, 95% CI 0.78–0.83) and rectal cancer (RER 0.73, 95% CI 0.71–0.76). The survival disadvantage for RCC remained present, even in cases with metastasectomy for liver-only disease (LCC: RER 0.66, 95% CI 0.57–0.76; rectal cancer: RER 0.84, 95% CI 0.66–1.06).

Conclusions

This study showed significant differences in relative survival between primary tumor locations in synchronous mCRC, which can only be partially explained by distinct metastatic sites. Our findings support the concept that RCC, LCC and rectal cancer should be considered distinct entities in synchronous mCRC.

Right-sided vs. left-sided obstructing colonic cancer: results of a multicenter study of the French Surgical Association in 2325 patients and literature review

PURPOSE

Few studies compared management and outcomes of obstructing colonic cancer (OCC), according to the tumor site. Our aim was to compare patient and tumor characteristics, postoperative and pathological results, and oncological outcomes after emergency management of right-sided vs. left-sided OCC.

METHODS

A national cohort study including all consecutive patients managed for OCC from 2000 to 2015 in French surgical centers members of the French National Surgical Association (AFC).

RESULTS

During the study period, 2325 patients with OCC were divided in right-sided (n = 819, 35%) and left-sided (n = 1506, 65%) locations. Patients with right-sided OCC were older, more frequently females, and associated with comorbidities, history of cancer, or previous laparotomy. Surgical management was more frequently performed for right-sided than left-sided OCC (99 vs. 96%, p < 0.0001). Tumor resection was more frequently performed in right-sided OCC (95 vs. 90%, p < 0.0001). Among the resected patients, primary anastomosis was more frequently performed in case of right-sided OCC (86 vs. 62%, p < 0.0001). Definitive stoma rate was lower in right-sided location (17 vs. 46%, p < 0.0001). There was no significant difference between locations in terms of cumulative morbidity, anastomotic leak, unplanned reoperation, and mortality. Five-year overall and disease-free survival rates were significantly lower in right-sided OCC (43 and 36%) than in left-sided OCC (53 and 46%, p < 0.0001 and p = 0.001, respectively).

CONCLUSIONS

Although patients with right-sided OCC are frailer than left-sided OCC, tumor resection and anastomosis are more frequently performed, without difference in surgical results. However, right-sided OCC is associated with worse prognosis than distal location.